1. Field of the Invention
This invention relates to a watercraft, and more particularly to a personal watercraft having an improved hull structure.
2. Description of the Related Art
Some personal watercrafts include a hull structure provided with a bulkhead for reinforcement that is joined to both the hull and a deck. According to this structure, the reinforcing effect can be achieved while keeping the weight of the hull low. However, an engine and a support portion (bearing portion) of an impeller shaft of a propulsion device are fixed directly to the hull without utilizing the bulkhead, so that it is difficult to accurately determine positions in which these parts are fixed.
Other examples of the hull structure of the personal watercraft include the hull structure disclosed in, for example, Japanese Patent No. 2826273. This hull structure is provided with the outer hull molded and constituting the lower portion of the hull, and the inner hull molded and disposed so as to be opposed to only the inner surface of the bottom wall of the outer hull. This inner hull extends in the longitudinal and lateral directions of the outer hull, and is joined to the bottom surface of the outer hull via ribs formed on both side portions thereof. This structure enables the strength of the hull to be improved. Moreover, since the inner hull is formed so that the engine, the fuel tank, the water muffler, the bearing supporting the impeller shaft of the propulsion device thereon, and the electric part box are mounted thereon, the dimensions of mount portions for these parts can be set at once. Accordingly, accurately determining the positions in which these parts are fixed can be done easily, and the assembling efficiency is improved. However, such a double hull structure having the outer and inner hull causes the weight of the hull to increase.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a personal watercraft having a hull structure, capable of reducing the weight of a hull while maintaining the rigidity and assembling efficiency of the hull at high levels.
According to an aspect of the present invention, a personal watercraft has a hull, a deck, and an inner frame member joined to an inner surface of the hull, the inner frame member having an engine mount portion that supports an engine thereon and extends from a middle portion to a rear portion of the hull, an impeller shaft support region that supports thereon an impeller shaft of a propulsion device driven by the engine, and a bulkhead that extends in the lateral direction of the hull.
According to this structure, the inner frame member is provided over only a part of the whole length of the hull, i.e., this member is short, so that the weight of the hull decreases. Since the bulkheads that extend in the lateral direction of the hull are joined to an inner surface of the hull and divide the hull into plural compartments, the rigidity of the hull is improved. Moreover, since the inner frame member has an engine mount portion and an impeller shaft support region, the accuracy of positions in which the engine and the impeller shaft are fixed is improved. Therefore, the centering of the engine and impeller shaft thereof is done easily, and the hull assembling efficiency is improved.
It is preferable that the bulkhead that extends in the lateral direction of the hull is provided in the inner surface of the hull away from and forward of said inner frame member. With this structure dividing the hull into multiple compartments, the rigidity of the hull is improved.
It is preferable that the inner frame member is joined to both the inner surface of said hull and the deck via adhesive layers. With this structure, the rigidity of the hull and deck is improved.
These objectives as well as other features and advantages of the present invention will become more apparent to those skilled in the art from the following description with reference to the accompanying drawings.